1. Field of the Invention
This invention relates to roller bearings and more particularly to improvements in the outer race member of roller bearings.
2. Description of the Prior Art
My invention contemplates the use of the outer race member of roller bearings as backup rollers against straightening rolls by which means sheet strip is straightened as one of the last operations in manufacturing steel sheet. Briefly stated, steel sheet prior to being coiled or sheared and packed for shipment to consumers, passes through a roll mill having straightening rolls which are relatively long and small diameter rolls. This operation serves to eliminate unevenness of steel sheet. Straightening rolls are precision ground so that the finished product will have a smooth surface and even thickness throughout. To accomplish this operation, the straightening rolls between which the product passes is provided with backup rollers laterally spaced apart along the length of the straightening rollers. These backup rollers are the outer race members of roller bearings, the inner race members of which are mounted on shafts which are adjustably movable so that the outer race member of the roller bearings mounted thereon may be made to bear against the straightening rolls with the force necessary to support the straightening rolls and thereby prevent flexing thereof as the rolls work the product to a finish surface as it passes therethrough.
The difficulties experienced in the prior practice resulted from the use of the outer race of the roller bearings as an area of applied force to maintain the straightening rollers of the roller mill axially rigid as it works the steel sheet. The surface contour across the outer race member of conventional roller bearings is such that after normal wear, some misalignment may occur causing the longitudinal line contact of the outer race member with the straightening roll, to shift and localize as a point contact adjacent the end or corner of the outer race member. The outer race roller of conventional bearings are provided with a substantially flat surface from end face to end face, that is, having a 1/1000th inch crown, which means that the crown radius is 1000 inches. For example, across a 2 inch wide roller bearing having a diameter of 3.5 inches, and a 1/8th inch corner radius provided between the end face of the outer race member and the roller surface, the point at which the 1/8th inch corner radius meets the 1000 inch radius roll surface of the outer race member, a definite and perceptible line or ridge is developed. This line is sufficiently pronounced, that the force exerted by the roller surface of the outer race member against the straightening roll, a wear line is worked circumferentially into the straightening roll and then impressed into the steel sheet passing through the roll. This necessitates stopping the straightening operation upon the appearance of the marked surface of the steel sheet to replace the straightening roll with new rolls or reground rolls, and also replace the worn bearings.